Method of forming rotors.



C. A. PARSONS.

METHOD OFYFORMING ROTORS. APPUCATION FILED lULY 6. ms.

Patented Sept. 26, 1916.

2 SHEETSSHEET l rai- - C. A. PARSONS.

METHOD OF FORMING ROTORS.

APPLlCATlON HLEDJULY s. 1915.

PatentedSept. 26, 1916.

2 SHEETS-SHEET 2.

lnvenlfor; ar 5 A Parse/r5 it/Com UNITED STATES. PATENT OFFICE. 9

CHARLES ALGERNON PARSONS, 0F NEWCASTLE-UPON-TYNE, ENGLAND.

METHOD OF FORMING ROTORS.

To all whom it may concern Be it known that I, CHARLES ALGERNON PARSONS, K. C. B., a subject of the King of Great Britain and Ireland, and residing at Heaton lVorks, Newcastle-upon-Tyne, in the county of Northumberland, England, have invented certain new and useful Improvements in and Relating to Methods of Forming Rotors, of which the following is a specification.

The present invention relates to method of forming rotors suitable for high surface speeds, and adapted for use in connection with turbines, gear wheels, dynamo electric machines and any other machines requiring a rotor of appreciable length which can be safely rotated at high speeds.

The object of the present invention is to provide a construction of rotor which shall have the highest possible factor of safety with the least possible weight, and which shall have the maximum rigidity to resist bending, and the highest critical speed for whipping, and be therefore capable of running without vibration at a very high rate of revolution.

The present invention consists in the method of forming rotors for high surface speeds and high rates of revolution hereinafter described.

In carrying the present invention into effect according to one form, a billet of metal which may be either cast or wrought to the approximate form of the exterior of the finished rotor, is taken. This billet is then turned and otherwise treated to bring its exterior to the dimensions required, and suitable journals are formed upon it. Grooves are then turned in the rotor of such depth as will leave the required diameter of boss to form the body of the rotor. These grooves are of such width as will permit the insertion of suitable tools'for the purpose of hollowing out the interior of the billet to form the light rims of the wheels and give the required contour to the webs joining these to the rim. It will be understood that the grooves are separated by portions of the periphery of the rotor which represent the width of the wheel rims. The sides of the end wheels are also hollowed out to provide the same contour for the end wheels as for the remaining wheels.

In some cases groups of wheels may be Specification of Letters Patent. Patgnted Sept 26, 1916. Application filed July 6, 1915.

Serial No. 38,309.

formed, separated bv plain portions of rotor of either the full diameter of the wheels or of a reduced diameter, the whole being wrought out of one piece of metal. Again, in some cases a group of wheels may be formed, having alongside it a plain portion of either the full diameter of the wheels or of a reduced diameter, the whole being wrought out of one piece of metal.

The peripheries of the wheels and the plain parts if any are suitably finished or furnished to suit the purpose for which the rotor is intended.

It is well known that the most suitable form of wheel for high peripheral speeds is one consisting of a light rim and a heavy boss connected by a tapered web which increases in thickness toward the boss. With such a construction when suitably proportioned, the stresses arising from the centrifugal forces of the wheel itself, and of the parts carried by the rim, tend to be uniformly distributed throughout the wheel. The important advantage arising, therefore, from the constructions indicated, viz., rotors comprising a plurality of such wheels, and wrought out of a single piece of metal, is that while the parts are of such a form as to give the highest factor of safety under centrifugal stress, the rotor as a whole has a greater rigidity, and consequently a higher critical speed than in the case where separate wheels of this type are forced or shrunk on to a central shaft. Rotors of this construction, therefore, are eminently suitable for high peripheral speeds and high rates of revolution.

The deflection in a rotor constructed according to the present invention is governed mainly by the diameter left at the bottom of the grooves between the wheels or the diameter of the plain portion uniting groups of wheels, whereas in the case of the known construction employing a shaft with separate or shrunk on wheels, the deflection depends upon the diameter of the central shaft itself, and the deflection or tendency to deflection is therefore considerably greater.

The reduction or deflection arising from the present constructions obviously raises the speed at which critical vibration and whipping will take place, and therefore permits of the rotor being run at a considerably higher number of revolutions per minu e than is possible with any bu lt-up constructions of the same Weight and maximum diameter.

Referring to the accompanying drawingsz-Figurel shows one form of rotor constructed according to the invention. Figs. 2 and 3 show other forms.

In the rotor illustrated in Fig. 1, the billet isfirst east or Wrought to the approXimate exterior form of the finished rotor, and is then turned to bring its exterior a (1 (1V to the dimensions required, and suitable journals Z) Z) are formed upon the ends. Grooves 0 0 are then turned in the rotor of such depth as Will leave the required diameter of boss, and of such Width as Will permit the insertion of suitable tools for the purpose of holloiving out the interior. The sides of these grooves and the side faces of the billet are then hollowed out as shown at d to form the light rims and give the required contour to the Webs e e e.

In the form of the invention shoivn in form the Wheels are in groups joined by a reduced portion.

In the form of carrying out the invention shown in Fig. 3, the same method of manufacture is adopted, but the rotor in this case comprises a group of Wheels and an extended portion of reduced diameter situated to one side of the group.

Having now described my invention What I claim as new and desire to secure by Letters Patent is The method of forming a rotor suitable for high surface speeds which consists in firstly, forming a billet approximately to the external shape required; secondly, turning the outer surfaces to the required dimen sions; thirdly, forming grooves for the insertion ofsuitable tools and fourthly, hollowing out the sides of such grooves to form rims and Webs, substantially as and for the purposes described.

In testimony whereof I affiX my signature;

CHARLES ALGERNON PARSONS.

lVitnesses:

FREDERICK GoRDoN HAY Bnnrono', lVILLIAM DAGGETT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Vt'fashin'gton, D; 0; 

